In most conventional automobiles, electricity for operating various vehicle electrical components, such as the vehicle lights and HVAC, is produced by an alternator. Typically, work done by an internal combustion engine (ICE) is converted, by the alternator, to an alternating-current (AC). An AC/DC converter converts the AC current to DC and passes the resulting current to a rechargeable low-voltage battery—i.e., the conventional 12-Volt (12V) battery. Because too much or too little voltage can damage or weaken the battery, a voltage regulator intermediates between the alternator and the battery and ensures that the appropriate voltage is introduced to the battery.
The efficiency with which automobiles generate and use power has increased considerably in the past few decades and efforts to further improve power efficiency and related benefits to mileage continue. Developments include use of a basic regulated voltage control, improved electric and hybrid vehicles, and use of solar energy.
Basic regulated voltage control (or, basic RVC) systems were introduced in response to a determination that the low-voltage battery need not always be kept fully charged during vehicle operation—i.e., at a 100% state-of-charge (SOC). It was noticed that maintaining a SOC at or above about 80% was sufficient for vehicle operation.
Basic RVC controls electrical system voltage by regulating output voltage of a generator or alternator. The control is based on an estimated battery temperature, the battery SOC, and present electrical needs of the vehicle. While earlier vehicles maintained a generally constant system voltage at a maximum level, e.g., 13V or 14V depending on the low-voltage battery, vehicles having the basic RVC in connection with the same 12V power source were able to, based on vehicle conditions at the time, dynamically fluctuate the system voltage, e.g., between about 12V and the maximum (13V or 14V in the examples). This ability to fluctuate system voltage resulted in a lower average voltage per trip with lowered energy consumption.
With basic RVC, the battery charge, through the manipulation of system voltage, can be selectively lowered to values between 100% SOC and about 80% SOC. In terms of voltages, 80% SOC for a typical flooded, lead-acid 12V battery, would equate to about 12.8V (80% of the range between a 0% SOC value of 12V and a 100% SOC value of 13V).
Just the basic RVC usage improved fuel economy, extended battery life, extended lamp life, and extended switch life. Further improvements are now possible according to the teachings of the present disclosure, including an augmented, more-aggressive, RVC model selectively using solar energy that is stored in an augmented, low-voltage, energy source or received directly from a solar subsystem.
In current automobiles equipped with a solar subsystem, solar energy is used in various ways. There are numerous shortcomings to using solar energy in these ways. The technology of the present disclosure overcomes these shortcomings, resulting in improved power efficiency and related vehicle-mileage characteristics.